Drafting and scavenging apparatus



March 3, 1964 N. E. KLEIN 3,122,794

DRAFTING AND SCAVENGING APPARATUS Filed Feb. 14, 1961 INVENTOR. NORMAN E. KLEIN United States Patent M 3,122,794 DRAFTING AND SCAVENGING APPARATUS Norman E. Klein, Spartanburg, S.C., assignor to Deering Milliken Research Corporation, Spartanburg, S.C., a corporation of Delaware Filed Feb. 14, 1961, Ser. No. 89,214 3 Claims. (Cl. 19288) This invention relates to improved apparatus for handling textile fibers, and more particularly to an improved drafting arrangement for textile fibers.

In the art of drafting textile fibers it is highly desirable to reduce the fly in the air resulting from the drafting action. A further and perhaps more important object is better straightening of individual fibers during the drafting operation and the better drawing of the fibers into the main body of the fiber mass. Another important object is the drafting of fibers at high speeds. The present invention is directed to aiding in the effecting of these desirable objects.

According to the invention in its broad form, a drafting arrangement is provided wherein one or more of the drafting rolls, preferably the bottom front roll, is formed with a plurality of apertures in its circumferential surface, these apertures connecting to an internal cavity formed within the roll, and to which is applied a source of negative pressure relative to the outside atmospheric pressure, as for instance by a vacuum blower arrangement and a suitable conduit connection. The zone of application of the negative pressure to the cavity end of the roll apertures is preferably restricted to the zone adjacent the nip of the drafting roll with another drafting roll, and includes the zone immediately preceding the nip, as well as preferably including the zone immediately subsequent to the nip and extending to the point of tangency of the fibers leaving the roll.

Various other objects and features of the invention will become apparent to one skilled in the art from a reading of the following more detailed description of one preferred embodiment, taken in conjunction with the accompanying drawings wherein:

FIGURE 1 is a schematic view in perspective of an embodiment constructed according to the invention.

FIGURE 2 is a schematic line drawing showing the general path of the fibers through the drafting arrangement, as viewed from one end of the drafting rolls.

FIGURE 3 is an enlarged and more detailed partially cutaway view of the apertured roll of FIGURE 1.

FIGURE 4 is a partial cutaway view of the stationary suction conduit which extends into the cavity formed in the apertured roll.

Referring now to the figures of the drawing, the invention is illustrated as applied to a conventional downtwister having a ring and traveler takeup 11 and a fiber drafting arrangement generally indicated at 13. While this particular embodiment is preferred and is most applicable to s inning from roving, it will be apparent to those skilled in the art that the invention may also be applied to roving frames on which roving is formed from sliver or on sliver-to-yarn spinning frames.

A roving 15 or other rope of staple fibers is passed through a conventional trumpet guide 17 to the drafting roll assembly 13, including the conventional first and second pairs of rolls 19, 21, 23, 25 and thence to the third pair of rolls 27, 29 which form the final or front pair preceding the twisting and takeup of the fibers by the ring and twister takeup 11. The roll 29 has a plurality of apertures 31 formed in its circumferential surface and preferably extending in a discrete relatively small width band encompassing the entire circumference. The apertures 31 extend through the roll 29 to a cylindrical cavity 3,122,794 Patented Mar. 3, 1964 33 formed therein and in which a suction conduit 35 is removably supported in stationary relation as by a portion of the stationary frame 37. The suction conduit 35 has an open mouth 35a which is preferably convex and conforms closely to the circumferential curvature of the cavity 33 formed in the roll 29. Also, in order to better concentrate the fibers in a desirably narrow band and in order to conserve on the power required to maintain a working negative pressure differential, the width of the convex conduit mouth 35a taken along the length of the roll is preferably restricted to a small zone adjacent the fiber flow path. The angular extent of the open convex conduit mouth extends from a zone preceding the nip zone N of the two rolls 27, 29 and to a zone tangential to the line of departure of the fibers from the roll, this angular extent in the preferred embodiment being materially less than 360, and preferably less than and encompassing the apertures 31 in the roll 29 within this angular extent.

The suction conduit is connected, preferably through a filter 39 to a suitable vacuum source 41, which may take the form of a blower having its suction side connected to the conduit 35 through an intermediate line 43 and filter 39.

While such is not a necessity for the basic operation of the invention it may be desirable to employ an external surface vacuum scavenging system adjacent the external circumferential periphery of the apertured roll 29 in order to scavenge from the roll surface any fibers which inadvertently remain on the roll 29 after the twisted fiber strand Y leaves the roll. For this purpose a hollow tube 44 having a small width slot 45 formed therein may be employed in conjunction with the vacuum source 41, the slot 45 being disposed beneath the lower peripheral surface of the roll 29, as best seen in FIGURE 2.

At least one of each of the pairs of drafting rolls is suitably driven from a drive source 46 through a suitable mechanical drive 47 connection, such as a gear train or cog belt drive of desired speed ratio proportions. As seen in FIGURE 3, the drive to the apertured front drafting roll may be through a cog belt 47a and a gear 47b centrally disposed on a common shaft 49 between two adjacent spinning positions, the shaft having formed on its opposite ends the respective two apertured rolls 29 for the two spinning positions. The shaft 49 may be rotatably mounted in suitable bearings 51 suitably mounted in stationary relation on the spinning frame, and the suction conduits 35 may extend into the respective apertured rolls through their opposite open ends.

In operation, the rope of textile fibers 15 is passed through the forming trumpet 17 and drafting assembly 13 to the ring and traveler twister takeup 11. Differing, however, from the conventional drafting of fibers, the apertured roll exerts a sucking action on the fibers in the zone immediately preceding the nip N and subsequent to the nip N of the rolls 27, 29, due to the negative pressure differential between the cavity 33 and the outside of the roll 29 in the arcuate zone of the open suction conduit mouth 35a. This causes the fibers approaching and leaving the nip of the rolls to be drawn toward closer proximity to the surface of the roll, aiding in the compacting and control of the fiber mass and in the reduction of lint fly; and in the zone immediately preceding the nip N of the rolls this sucking action on the fibers through the roll apertures 31 will tend to draw the succeeding fibers from the fiber mass moving between the pair of rolls 23, 25 and the rolls 27, 29 into a more straight configuration. This is particularly brought about by the pneumatic sucking and inter-fiber pulling action on the fibers in an angular zone preceding the nip of the rolls.

The pneumatic pulling action exerted on the fibers as they approach the suction zone preceding the nip in coopelation with the angular or rotational movement of the roll surface in frictional contact with said fibers effects a gentle plucking action as distinguished from the more Positive nip plucking action afiorded by conventional front nip rolls, The fibers which have been pulled and lie in part on the. perforated surface of roll 29 serve by their frictional cohesion with the subsequent fibers to drag such subsequent fibers onto. the roll as these preceding fibersv are pneumatically held and progressed on the rotatingroll surface. This inter-fiber plucking plus the pulling action caused by the movement of the surface of rotating roll 29 preceding the nip zone N effects a general straightening of the. fibers prior to, their passage through the delivery rollv nip. Moreover, this action has particular merit in straightening out leading hooks. The straightened fibers are. then nipped in sequence in respect to their ordered lay in the fiber group (i.e. rope of sliver or roving) as such successively approach and reach the nip N;

The fibers leaving the nip N of the rolls 27, 29 are, twisted by the twisting action of the ring and traveler takeup. 11', andv proceed thereafter in the form of yarn Y or other twisted strandular product to the takeup bobbin B.

As further advantages of the present invention it will be noted that a partial vacuum. exists in the approach areato the nip. N of: rolls 27, 29 as opposed to the usual Slight positive air pressure buildup in this region, and;

this: facilitates increased. drafting speeds since the fibers do. not tend to spread out as they approach the, nip as in conventional drafting arrangements at high speeds due tothe air pocket and laterally outward air movement in the nip approach region. A further advantage lies in the scavenging action which the roll 29 exerts on the adjacent top roll 27, thus tending to, reduce any necessity for clearing or cleaning of this roll 27.

While the invention has been described with reference to only one preferred physical embodiment constructed in accordance therewith, it will be apparent that various modifications and improvements may be made without departing from the scope and spirit of the invention. For

instance, the apertured roll may in some instances be disposed in another position, such as by forming one of the second or middle pair of rolls, or two or more aperturedrolls may be employed, e.g;, one in each of the middle and finalpair of drafting rolls. Accordingly, it will be understood that the invention is not'to be limited by this;

illustrative embodiment but only by the scope of the appended claims.

That which is claimed is:

1. A drafting arrangement comprising roll support bearing means, two coaxial rotatable circumferentially pert r d sca enging and draf ing ro ls. carried in oppositely extending cantilever relation on said bearing means, two stationary vacuum conduits extending into the opposite free ends of said cantilever carried rolls, saidstationary vacuum conduits having an arcuate mouthed opening of less than approximately in are opening within said cavity and in registry with a portion of less than approximately 180 in arc of said apertures, and a'commondrive connection to said rolls adjacent the common connectingcenter supported portion thereof.

2.. Textile drafting apparatus comprising a plurality of drafting rolls including a pair of rolls in peripheral nip! forming engagement with each other, one of said pair of rolls being a scavenging roll having a cavity therein and having a plurality of apertures formed in the cir-w cumferential periphery of said roll and extending between said periphery and said cavity and, means for connecting the cavity end Of. a segment, portion, of said apertures to; a source of negative pressure which includes a pneumatic conduit having an arcuate mouth portion communicating with the cavity of said aperture, said arcuate mouth por-. tion being less than approximately 180 in arc opening and. being in registry with a portion of less than 180 in arc of said apertures with said arc portion of said aper ture including the nip zone of said one roll.

3. The structure of claim 2 including an apertnred secondary scavenging means connected to a source of negative pressure and positioned with respect to said one roll such that the apertured portion of said scavenging means: is proximate the apertured peripheral portion of said one, roll outside, the arcuate extent defined by said conduit opening.

References Cited in the file of this Patent UNITED STATES PATENTS 

1. A DRAFTING ARRANGEMENT COMPRISING ROLL SUPPORT BEARING MEANS, TWO COAXIAL ROTATABLE CIRCUMFERENTIALLY APERTURED SCAVENGING AND DRAFTING ROLLS CARRIED IN OPPOSITELY EXTENDING CANTILEVER RELATION ON SAID BEARING MEANS, TWO STATIONARY VACUUM CONDUITS EXTENDING INTO THE OPPOSITE FREE ENDS OF SAID CANTILEVER CARRIED ROLLS, SAID STATIONARY VACUUM CONDUITS HAVING AN ARCUATE MOUTHED OPENING OF LESS THAN APPROXIMATELY 180* IN ARC OPENING WITHIN SAID CAVITY AND IN REGISTRY WITH A PORTION OF LESS THAN APPROXIMATELY 180* IN ARC OF SAID APERTURES, AND A COMMON DRIVE CONNECTION TO SAID ROLLS ADJACENT THE COMMON CONNECTING CENTER SUPPORTED PORTION THEREOF. 